Yes, the food pyramid, with a base of "at least 11 servings of healthywholegrains" is one manifestation of the "diet-heart hypothesis," which traces back to Ancel Keys and his "Seven Countries" study. His hypothesis was that higher levels of dietary fat raise cholesterol in the blood and leads to higher heart disease rates. It's called the Seven Countries study because it examined statistics relating to fat consumption and heart disease rates in seven countries (Greece, Italy, Spain, South Africa, Japan, and Finland). The results "proved" his hypothesis. The problem is that more comprehensive data from a wider set of countries does not support this theory (there are countries such as France, Holland and Norway where people eat a lot of fat but have little heart disease and countries such as Chile and Russia where fat consumption is low but the rate of heart disease is high). Keys later insisted that these were the only available data and he was not cherry-picking. But whether that's true or not, the fact is that available data does not support this relationship between fat consumption and heart disease. The recommendations based on that theory, i.e., a low-fat (read "high carb") diet to prevent heart disease, are therefore inherently unsubstantiated.